Are u testing it as you go? You need to test it..

Algaecide will take a while 2 work - brush pool now then clean filter - run pump x24 hr. brush again n clean filter again - pool should be clearing - test water - correct and then shock again - if still green call pool company :)

How many gallons are in the pool? Are you new to owning it?

What is your pool size and current chemical readings for pH, Free Chlorine, Total Chlorine, and Total Alkalinity?
The shock with 6 gallons of liquid chlorine seems like a lot...and would likely be enough. Brush the pool and run filter for 24 hours.

This forum is better for your question:
http://www.troublefreepool.com/index.html

If water doesn't clear after adding chlorine, you could have metals in the pool (iron or copper, or both). Take a sample of your water to a pool store and have them test for metals. If metals are present, a sequestrant chemical treatment will need to be added.

All of my readings for ph, chlorine, alkalinity, metals are all okay. I am working with a pool store. Pool is 10,000 gals (50,000 L) and have been following their instructions. It is just not working. Have just super shocked for the second time so will see what happens now.

Thankyou mmilos. i have gone to that site and am finding it immensely helpful. Thanks also to every one for their comments and suggestions. Have had this pool for 12 years and have never run into a problem as serious as this!!!